Your Ultimate Breakdown of Polyhydroxy Acid (PHA) in Skincar

There’s a reason acid-based skincare products are a staple in beauty routines—they exfoliate, brighten, smooth, and transform your skin like few other ingredients can. While many types of acids cater to different skin needs, polyhydroxy acid (PHA) is emerging as a gentler, multitasking option worth knowing. So what exactly is PHA? We asked the experts and dug into the details. Read on to discover why this next-gen acid deserves a spot in your skincare routine.

What Is PHA?

Polyhydroxy acids (PHAs) are the latest addition to the family of exfoliating acids in skincare. Technically a type of AHA, PHAs have a larger molecular structure than their more familiar counterparts like glycolic or lactic acid. Because of this, they remain on the surface of the skin, working gently to loosen dead skin cells without penetrating too deeply—making them an ideal exfoliant for sensitive skin.

But PHAs offer more than just exfoliation. They also have antioxidant and hydrating properties, making them a well-rounded option for anyone looking to brighten, smooth, and nourish their skin—all with minimal irritation. PHAs are especially suitable for individuals with skin conditions like rosacea or eczema, who may not tolerate stronger acids such as AHAs or BHAs.

Benefits of PHAs

PHAs bring a lot to the table when it comes to skin health. Some of the key benefits include:

• Gentle on sensitive skin: Their larger molecular size means they absorb more slowly and don’t penetrate as deeply, reducing the risk of irritation.

• Non-irritating exfoliation: PHAs effectively slough off dead skin without causing redness or stinging, even for those with delicate skin.

• Hydration support: PHAs act as humectants, helping the skin retain moisture, which can lead to improved texture, plumpness, and a glowing complexion.

• Anti-inflammatory properties: These acids help calm inflammation and support overall skin barrier health.

• Antioxidant protection: PHAs fight oxidative stress and help prevent damage from environmental aggressors.

• Combats glycation: They also help counter glycation—a process that degrades collagen and elastin, contributing to signs of aging.

  
  

AHA vs. BHA vs. PHA: What’s the Difference?

• AHAs (Alpha-Hydroxy Acids): These include glycolic, lactic, and citric acids. They're known for their deep exfoliating action, helping to reveal brighter, smoother skin beneath the surface. Due to their potency, they can cause irritation in some skin types and are best used a few times a week.

• BHAs (Beta-Hydroxy Acids): Salicylic acid is the most well-known BHA. Unlike AHAs, BHAs are oil-soluble and can penetrate pores, making them effective for treating acne and oily skin concerns like clogged pores and texture irregularities.

• PHAs (Polyhydroxy Acids): Considered the gentler cousin of AHAs, PHAs provide surface-level exfoliation without stripping the skin. They’re ideal for sensitive skin types and offer additional benefits like hydration, antioxidant support, and anti-aging effects.

  
  

Are There Side Effects to Using PHAs?

One of the key reasons PHAs are so popular is their low risk of side effects. They work on the skin’s surface, making them less likely to cause irritation or peeling. That said, they are still active acids—so those with very sensitive skin should perform a patch test before full application.

Overuse can lead to dryness or mild irritation, especially if combined with other active ingredients. Start slow—perhaps a few times a week—and increase frequency as your skin adjusts. Like all exfoliants, PHAs can increase sun sensitivity, so daily sunscreen use is non-negotiable when using them.

Skin Considerations

The great thing about PHAs is their compatibility with nearly every skin type. Whether your skin is dry, oily, or somewhere in between, PHAs are generally well-tolerated—even by those with sensitive or reactive skin. Thanks to their gentle action, they’re less likely to cause irritation compared to other exfoliants. That said, it’s still best to introduce them gradually, avoid applying them to broken skin, and monitor for any sensitivity—especially if you're prone to acne-related inflammation.

How to Use PHAs

PHAs can be found in a wide range of products—from toners and masks to moisturizers and leave-on exfoliants. They work most effectively when left on the skin long enough to dissolve the bonds between dead surface skin cells, encouraging smoother and brighter skin.

In some cases, PHAs are added to AHA formulas to help sweep away residual debris on the skin’s surface. They’re also commonly included in products like serums—not as the primary exfoliant, but to gently refine the skin and enhance product absorption. In other formulations, PHAs take center stage as the key active ingredient.

Another benefit? PHAs pair well with many other skincare staples. They can be layered with hydrating ingredients like hyaluronic acid or ceramides, and even used alongside milder forms of retinoids. However, if you're already using physical scrubs or potent actives, it’s wise to alternate their use to prevent over-exfoliation.

PHAs also play nicely with more advanced skincare routines. They can be incorporated alongside treatments targeting acne, pigmentation, or signs of aging. When used thoughtfully, they may complement retinoids, hydroquinone, and even follow-up care after cosmetic procedures like laser treatments or microdermabrasion—though such combinations should always be done with professional guidance.

FAQs

Can I use PHA every day?

Yes, PHAs are gentle enough for daily use for most skin types. Because they have a larger molecular structure, they tend to stay on the skin’s surface rather than penetrating deeply, which helps minimize irritation. This also makes them hydrating as well as exfoliating. Many PHA-containing products can even be used twice a day, but it's usually a good idea to start by using them in your nighttime routine to see how your skin responds.

Can I use PHA and salicylic acid together?

Yes, PHAs can typically be used in combination with salicylic acid for a more comprehensive skincare routine. While PHAs offer gentle exfoliation and hydration, salicylic acid (a BHA) works deeper in the pores to combat oil and acne. These ingredients are often formulated together or used in the same routine to target multiple concerns—such as clogged pores, uneven texture, and dryness—without causing excessive irritation.

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II DISCLAIMER: Every skin is different, not everything works for everybody. I recommend you test the product before completely using any new product. II